So far so good. Once the box is back up go back into root mode and type:

root@% smartd -oe /dev/ad1

Hopefully your drive should be back up. If not you can run some extended smart tests on it. If you’ve lost your partitions you can repartition the disk by first going into cli mode and then:

root> request system partition hard-disk
WARNING: The hard disk is about to be partitioned. The contents
WARNING: of /altroot and /altconfig will be saved and restored.
WARNING: All other data is at risk. This is the setup stage, the
WARNING: partition happens during the next reboot.
Setting up to partition the hard disk ...
WARNING: A REBOOT IS REQUIRED TO PARTITION THE HARD DISK. Use the
WARNING: 'request system reboot' command when you are ready to proceed
WARNING: with the partitioning. To abort the partition of the hard disk
WARNING: use the 'request system partition abort' command.
root> request system reboot
Reboot the system ? [yes,no] (no) yes